A heat warning: Don’t forget trees

Crops and gardens aren't the only vegetation that need a little extra water during the summer.

With temperatures reaching well into the 90s and the recent lack of rain, Leavenworth County extension agent Sy Nyhart said an extra effort should be made to water trees.

"The younger and smaller the tree, the more concern there is," Nyhart said. "Right now they don't have a whole lot of water reserve under the ground. Smaller trees will need water quicker than bigger trees because there are not as many roots to find and absorb water."

He said hot, dry winds suck moisture from a tree causing it to transpire. If a tree is big enough and has a strong root system, Nyhart said it can withstand the lack of water for awhile by losing some of its leaves. But it eventually will dry up and die.

He said in order to maintain enough water to survive, trees should receive deep soakings.

"The thing you don't want to do is go out with the garden hose and sprinkle water on the tree," he said. "You want to turn the hose on and let it run."

Because tree roots are found two to three feet below the surface, Shirley Tice, co-chairman of the Tonganoxie Tree Board, said water should be allowed to trickle and soak into the ground for two to three hours.

"This allows time for the roots to absorb the water," Tice said.

Nyhart said avoid watering right around the trunk of the tree.

"Water out around the drip line where the water drips right off the edge of the tree," he said. "That's where the roots will be."

A thorough soaking will guarantee that water will reach the roots before it evaporates, Nyhart said.

"We really recommend that you water once a week. For larger trees, two to three times a month is fine, but you'll have to water heavier," he said.

Trees should have about an inch of water a week, Nyhart said.

"If it rains an inch, you shouldn't have to water that week," he said. "If you get two inches, you might not need watering for two weeks. There are no absolutes. Everything depends on what else is going on."

The early morning is the best time to water trees, he said.

"It avoids the possibility of diseases," he said. "In the morning, the sun has a chance to dry the excess water off."

The longer the leaves and the grass stay wet, the more susceptible the tree is to disease.

Even though trees need to be watered thoroughly, Nyhart said it's important not to over-water them.

"By watering too often, you can exclude the oxygen in the soil. There's no air for the roots to live on," he said. "You end up drowning the tree."

Nyhart said he also discourages fertilizing during summer months.

"Fertilizing encourages the tree to grow more and encourages it to use more water, which we're already short of," he said.